Water-based lubricants

ABSTRACT

Water-based lubricants having anti-wear and extreme pressure properties containing from 0.1 to 5 percent by weight of an additive package consisting essentially of 0.005 to 4.0 percent of an alkyl phosphonate or an amine adduct thereof; 0.003 to 0.60 percent of an alkaline earth metal hydroxide and or a dye, an ethoxylate of an acid or an alcohol; the balance water.

BACKGROUND OF THE INVENTION Field of the Invention

This invention relates to a water base lubricant having anti-wear and extreme pressure properties comparable with those of currently used hydraulic mineral oils.

Heretofore, emulsion type hydraulic fluids and other water based lubricating fluids have been found deficient in extreme pressure and anti-wear properties particularly in regards pump wear. However, from the standpoints of economics and fire resistance, water-based lubricants remain attractive.

SUMMARY OF THE INVENTION

The lubricant compositions of the invention comprise 0.005 to 4.0 in weight percent of a C₆ -C₁₈ alkylphosphonate or adduct thereof; 0.005 to 4.0 percent of an acid or an alcohol ethoxylate; 0.003 to 0.60% of an alkali earth metal hydroxide and/or of a dye, and 95 to 991/2 percent water.

Suitable alkylphosphonates are disclosed and claimed in coassigned U.S. Pat. No. 3,793,199 such as ammonium salts of alkyl alkanephosphonates represented by the formula: ##STR1## in which R is a substantially straight chain aliphatic radical having from about 11 to 40 carbon atoms, R' is a lower aliphatic radical having from one to eight carbon atoms, R² is a hydrocarbyl radical having from 1 to 40 carbon atoms and R³ and R⁴ are hydrogen, a hydrocarbyl radical having from one to 40 carbon atoms, or a substituted hydrocarbyl radical having amino, alkylamino or hydroxyl functional groups.

Ethoxylates suitable for the invention include: ethoxylated oleic acid, ethoxylated dimer acid, ethoxylated rosin fatty acids and the like.

Dyes suitable for the present invention include: methyl orange, thymol blue, p-naphthyl benzene and the like.

Table I-IV below compare Four Ball Test results obtained with various formulations of the invention. The Load Wear Index (LWI) given in Table I and III indicates the load carrying property of a lubricating fluid. It is an overall index of the ability of a lubricant to prevent wear and welding at applied loads. Under the conditions of the test, specific loadings in Kilograms having intervals of 0.1 logarithmic units are applied to three stationary balls for ten runs. The actual test procedure is described in detail in ASTM D2783-71. In Tables I and III the antiwear action at each of the test loads is given by the AntiWear Number (AWN). AWN was determined as set forth in Lubrication Engineering (Vol. 51, 881-2, 1975). The Four Ball Weat Test which determines wear preventive characteristics in sliding steel-on-steel applications was carried out as described in ASTM D 2266-67, modified as set forth in Tables II and IV. These wear results are also given in terms of Anti-Wear Number to allow direct comparison of data from different loads, test durations and machines.

                                      TABLE I                                      __________________________________________________________________________     FOUR BALL LOAD WEAR INDEX TEST RESULTS WITH HYDROXIDE                          LUBRICANT     AWN Load, Kg                                                     1% A.sup.1 in H.sub.2 O                                                                   LWI                                                                               79  100 126 158 200   250                                        __________________________________________________________________________     No Ca(OH).sub.2                                                                           49 6.5 6.2 6.3 Weld                                                 +.00375% Ca(OH).sub.2                                                                     62 6.5  6.35                                                                              6.3 6.4 Weld                                             +.0075% Ca(OH).sub.2                                                                      49 7.3 6.1 6.05                                                                               Weld                                                 +.015% Ca(OH).sub.2                                                                       49 6.5 6.1 6.05                                                                               Weld                                                 +.030% Ca(OH).sub.2                                                                       39 6.2 6.2 Weld                                                                               --  --                                                          62;62                                                                             6.5;6.5                                                                            6.2;6.3                                                                            6.3;6.7                                                                            6.0;6.4                                                                            Weld;Weld                                        +.045% Ca(OH).sub.2                                                                       62 6.7 6.9 6.05                                                                               6.05                                                                               Weld                                             +.100% Ca(OH).sub.2                                                                       45 --  --  --  --  --    --                                         1% B.sup.2 in H.sub.2 O                                                        +.020% Ca(OH).sub.2                                                                       38 6.5 5.9 Weld                                                     +.040% Ca(OH).sub.2                                                                       48 6.5 6.5 5.7 Weld                                                 __________________________________________________________________________      .sup.1 "A" is 85/15 dimethyl tetradecanephosphonate and ethoxylated rosin      fatty acids.                                                                   .sup.2 "B" is 85/15 dimethyl tetradecane phosphonate and ethoxylated dime      acids.                                                                   

                                      TABLE II                                     __________________________________________________________________________     FOUR BALL WEAR TEST RESULTS WITH HYDROXIDE                                     1/2HR., 1800 RPM, 130° F.                                                                 Friction Coefficients                                        LUBRICANT AWN     7.5 kg      28 kg                                            1% A.sup.1 in H.sub.2 O                                                                  7.5 kg                                                                             28 kg                                                                              Mean                                                                               Max.*                                                                              Static                                                                             Mean                                                                               Max.*                                                                              Static                                   __________________________________________________________________________     No Ca(OH).sub.2                                                                          6.45                                                                               7.1 .11 --  .12 .092                                                                               .096                                                                               .092                                     +.0075% Ca(OH).sub.2                                                                     6.6 7.1 .089                                                                               .095                                                                               .095                                                                               .090                                                                               --  .090                                     +.015% Ca(OH).sub.2                                                                      6.8 7.4 .076                                                                               .087                                                                               .092                                                                                .0975                                                                             --  .10                                      +.030% Ca(OH).sub.2                                                                      7.9 7.9 .071                                                                               --  .080                                                                               .082                                                                               --  .099                                               6.5 7.3 .076                                                                               .087                                                                               .092                                                                               .084                                                                               --  .084                                               7.4 7.6 .081                                                                               --  .091                                                                               .081                                                                               .083                                                                               .091                                     +.045% Ca(OH).sub.2                                                                      7.4 7.1 .095                                                                               --  .095                                                                               .064                                                                               .078                                                                               .064                                     +.100% Ca(OH).sub.2                                                                      8.0 7.0 .068                                                                               --  .078                                                                               .076                                                                               .15 .084                                     1% B.sup.2 in H.sub.2 O                                                        +.020% Ca(OH).sub.2                                                                      7.3 7.5 .073                                                                               --  .078                                                                               .088                                                                               .089                                                                               .095                                     +.040% Ca(OH).sub.2                                                                      7.7 7.4 .091                                                                               --  .091                                                                               .090                                                                               .093                                                                               .093                                     __________________________________________________________________________      .sup.1 "A" is 85/15 dimethyl tetradecanephosphonate and the reaction           product of rosin fatty acid with 15 moles of ethylene oxide.                   .sup.2 "B" is 85/15 dimethyl tetradecane phosphonate and ethoxylated dime      acids.                                                                         *indicates absence of a clear maximum in the friction vs. time record.   

                                      TABLE III                                    __________________________________________________________________________     FOUR BALL LOAD WEAR INDEX TEST RESULTS WITH DYES AND                           COMPARISON WITH HYDRAULIC Oils                                                                 AWN Load, Kg                                                   Lubricant    LWI                                                                               50                                                                               63                                                                               79                                                                               100                                                                               126 158 200 250                                       __________________________________________________________________________     1% C.sup.3 in H.sub.2 O                                                                     62 --                                                                               --                                                                               6.5                                                                              6.3                                                                               6.7 6.4 Weld                                          +.01% phenolphthalein                                                                       62 --                                                                               --                                                                               6.7                                                                              6.2                                                                               6.2 6.3 Weld                                          +.01% thymol blue                                                                           49 --                                                                               --                                                                               6.5                                                                              6.3                                                                               6.3 Weld                                              +.01% methyl orange                                                                         39 --                                                                               --                                                                               7.3                                                                              >7.4                                                                              Weld                                                  +.01% p-naphtholbenzein                                                                     49 --                                                                               --                                                                               6.5                                                                              6.3                                                                               6.1 Weld                                              +.01% alkaline blue 6B                                                                      49 --                                                                               --                                                                               7.3                                                                               6.35                                                                             6.2 Weld                                              1% A in H.sub.2 O                                                              +.0120 methylorange                                                                         62                                                                +.01% p-naphtholbenzein                                                                     49                                                                Typical LWI Data for Commercial Oil-Based Antiwear Hydraulic Oils                         Nominal Viscosity                                                   Oil        SUS at 100° F.                                                                       LWI                                                    __________________________________________________________________________     A          150          31                                                     B          215          30                                                     C          315          37                                                     D          700          35                                                     E          1000         37                                                     __________________________________________________________________________      .sup.3 "C" consists of 0.03% Ca(OH).sub.2 and 1.0% of a mixture of 85/15       dimethyltetradecanephosphonate and ethoxylated rosin fatty acid.         

                                      TABLE IV                                     __________________________________________________________________________     FOUR BALL WEAR TEST RESULTS                                                    WITH DYES AND COMPARISON WITH HYDRAULIC OILS                                   1/2Hr., 1800 RPM, 130° F.                                                                      Friction Coefficients                                                AWN       7.5 kg      28 kg                                       Lubricant    7.5 kg                                                                             28 kg Mean                                                                               Max.*                                                                              Static                                                                             Mean                                                                               Max.*                                                                              Static                              __________________________________________________________________________     1% C in H.sub.2 O                                                                           7.4 7.6   .081                                                                               --  .091                                                                               .081                                                                               .083                                                                               .091                                +.01% phenothalein                                                                          7.9 7.6   .053                                                                               --  .061                                                                               .080                                                                               .081                                                                               .095                                +.01% thymol blue                                                                           7.9 7.4   .062                                                                               --  .071                                                                               .067                                                                               .074                                                                               .073                                +.01% methyl orange                                                                         8.0 8.0   .055                                                                               --  .063                                                                               .064                                                                               .069                                                                               .084                                +.01% p-naphtholbenzein                                                                     8.0 8.1   .061                                                                               --  .074                                                                               .062                                                                               .066                                                                               .081                                +0.1% alkaline blue                                                                         7.8 7.8   .079                                                                               --  .090                                                                               .080                                                                               --  .097                                1% A in H.sub.2 O                                                              +.0120 methyl orange                                                                        6.7 6.9   13.sup.a                                                                           --  .13 .095                                                                               --  .095                                +.01% p-naphtholbenzein 6.6                                                                 6.8 .13.sup.b                                                                            --  .13 .10.sup.a                                                                          --  .10                                     Typical Wear Results for Commercial Oil-Based Antiwear Hydraulic Oils (1       hour Tests at 40 Kg)                                                                      Nominal Viscosity,                                                  Oil        SUS at 100° F.                                                                       AWN                                                    __________________________________________________________________________     A          750          7.8                                                    B          215          8.3                                                    C          315          8.3                                                    D          700          8.3                                                    E          1000         8.7                                                    __________________________________________________________________________      *indicates absence of a clear maximum in the friction vs. time record.         .sup.a Smooth friction.                                                        .sup.b Extremely smooth friction.                                        

                                      TABLE V                                      __________________________________________________________________________                 AntiWear Number                                                                             Load-Wear Index                                                   Vanes+       AWN at                                                                              LWI,                                                                               Weld,                                        Test        Ring Ring                                                                               Vanes                                                                              100 kg                                                                              kg  kg                                           __________________________________________________________________________     Vickers Pump                                                                               5.9  5.6 8.1                                                       Four Ball (Wear, 1/2 h,                                                        130° F., 1800 rpm)                                                                  7.5 kg                                                                              28 kg                                                         Unused Sample                                                                              6.5  7.3     6.3  49  160                                          Unused Sample                                                                              6.4  7.1     6.1  49  160                                          After Vickers Test                                                                         6.5  6.9     6.1  39  126                                          After Rust Test                                                                            6.5  7.2     6.3  39  126                                          D665 Rust Test                                                                             10% Brown Rust, 80% Black Stain                                    D892 Seq. I Foam Test                                                                      Upper Foam Level 590                                                           Lower Foam Level 180                                                           Foam Level       410                                                           Foam Collapse, Vol. at 15 min.                                                                  390                                               Freezing Point                                                                             1.5° C. (34.7° F.)                                   pH          8.5                                                                Viscosity at 100° F.                                                                0.70 cs                                                            After Vickers Test                                                             __________________________________________________________________________

Table I shows that calcium hydroxide tends to enhance load carrying of two blends of a phosphonate and ethoxylate. Table II shows synergistic improvements of these blends to calcium hydroxide in both antiwear and antifriction action. Antiwear improvement with increasing calcium hydroxide occurs at 7.5 kg and an optimum occurs at 28 kg. Reduction of friction by calcium hydroxide is evident at both loads.

Table III shows that the load carrying of phosphonate/ethoxylate blends with or without calcium hydroxide is superior to commercial anti-wear hydraulic fluids based on mineral oil. After addition of dyes, the load carrying capacity of these blends remain superior to the hydraulic oils. Table IV shows that the dyes enhance the antiwear and antifriction performance of the blends. Three of the dyes in one blend provide antiwear performance at least equivalent to that of the lowest viscosity antiwear hydraulic oil.

In a functional test of the invention a vane pump test was carried out on a Vickers V104C Pump using as the lubricant a 1% water solution of 85/15 ratio dimethyl tetradecanephosphonate and the reaction product of 1 mole of rosin fatty acid and 15 moles of ethylene oxide and 0.03% of Ca(OH)₂. The pump test was run at 100 F. inlet temperature, 1200 rpm, and 750 psi output pressure.

The pump was running smoothly with a constant good flow rate of about 5 gallons per minute, at the conclusion of the 100-hour test. Weight loss of the cam ring due to wear was 3400 mg at the end of the test, while that of the vanes was 12 mg. These results are expressed as AntiWear Number (AWN) in Table V.

Completion of the Vickers test with a good constant pump flow demonstrates that lubricating by 99% water is technically feasible.

It will thus be seen that there is provided a composition in which the several objects of this invention are achieved, and which is well adapted to meet the conditions of practical use.

As various possible embodiments might be made of the above invention, and as various changes might be made in the embodiment above set forth, it is to be understood that all matter herein set forth or shown in the accompanying tables is to be interpreted as illustrative and not in a limiting sense. 

Having thus described our invention we claim as new and desire to secure by Letters Patent:
 1. Water-based lubricants for use in metal working processing and as hydraulic fluids comprising; in weight percent, from 0.005 to 4.0 percent of a C₆ -C₁₈ alkyl phosphonate or an amine adduct thereof; from 0.005 to 4.0 percent of an ethoxylated oleic acid, ethoxylated dimer acid, or a mixture of ethoxylated rosin fatty acids, from 0.003 to 0.60 percent of an alkali or alkaline earth metal hydroxide, balance water.
 2. The lubricant of claim 1, wherein said hydroxide is Ca(OH)₂.
 3. The lubricant of claim 1 also containing a dye of the group of methyl orange, thymol blue, and p-naphthyl benzene.
 4. The lubricant of claim 1 comprising an aqueous solution containing 1 percent by weight of 85/15 ratio of dimethyl tetradecanephosphonate and the reaction product of rosin fatty acid with 15 moles of ethylene oxide and 0.03 percent by weight of Ca(OH)₂. 